More than 150 workers were dramatically rescued from the Libyan desert as two RAF Hercules aircraft – backed by the SAS – pulled off a high-risk evacuation of British and other citizens.

As world leaders united to demand that Muammar Gaddafi face the full consequences of what Barack Obama called the "brutalisation" of his people, the defence secretary, Liam Fox, confirmed that the rescue had been a success, so far.

It is believed that units of British special forces secured runways south of Benghazi to allow the Hercules aircraft to land safely.

A statement from the Foreign Office said that the rescued workers had been met by consular officials and Red Cross staff when they landed in the Maltese capital, Valletta. "Once disembarked, the passengers will be given food and water and offered full consular assistance," a Foreign Office spokesman said. "This includes immigration processing and a medical. They will then be bussed to hotels, where they will stay overnight."

Last night the Foreign Office – which had been heavily criticised earlier in the week for being slow to get people out – said that up to 500 Britons remained in desert camps. "Nothing is complete yet," said a spokesman. Meanwhile HMS Cumberland was on its way back to Benghazi to evacuate the last Britons from the rebel-held city.

Plans for the emergency operation, carried out with the help of the SAS and members of the Special Boat Service who had been on standby in Malta, were finalised at a meeting of the government's emergency committee, Cobra. Government sources said the operation had been hazardous and complex, because the desert compounds were under threat from armed gangs and contained nationals from many countries.

David Cameron was in touch with leaders of other nations – including Germany, Italy and Turkey – to co-ordinate operations. In the international community there was agreement that once the evacuation was complete, the strongest action had to be taken through the UN and EU against the Libyan leader.

There were unconfirmed reports that Tony Blair had telephoned Gaddafi urging him to stop killing his own countrymen, and warning him that if he refused to do so, Nato troops might be sent in. The claims were made by one of Gaddafi's sons, Saadi, in a telephone interview from Tripoli.

As the rescue drama unfolded, on the streets of the city there was a standoff. According to journalists allowed access to Tripoli by the Libyan foreign ministry, the capital appeared divided between the quiet and controlled seafront areas, and the small alleys of the poorer neighbourhoods. In the less prosperous areas there were few signs of the security forces, which had abandoned the working-class Tajoura district after five days of anti-government demonstrations.

Troops were said to have opened fired on demonstrators who tried to march from Tajoura to Green square in the city centre overnight, killing at least five people. The number could not be confirmed. A funeral yesterday for one victim turned into another rally. "Everyone in Tajoura came out against the government. We saw them killing our people here and everywhere," Ali, 25, said.

Last night the operations of the British embassy in Tripoli were suspended and its staff flown to London. A Downing Street spokesman said that Cameron – keen to seize the initiative after a week of damaging headlines over the Foreign Office's earlier failings – was more determined than ever that Gaddafi be held to account: "The prime minister was clear that the Libyan regime would face the consequences of its actions. He agreed with counterparts that urgent action was needed through the EU and UN, including a tough sanctions package targeting the regime directly. The prime minister stressed that there could be no impunity for the blatant and inhuman disregard for basic rights taking place."

Those who arrived in Britain on charter flights described the panic. Iftikhar Ulhak, 59, a chemical engineer from Wimbledon in south London, said: "There were women, children, old people. It was terrible getting into the airport. It took us four hours despite the British embassy staff were there."

The Foreign Office said that it had helped evacuate 600 Britons, placing 450 on aircraft, boats and ferries, and advising a further 150.

The UN security council voted unanimously to accept a draft resolution imposing international travel bans on Gaddafi, his family and inner circle and freezing their assets. The list includes Gaddafi and eight of his children, as well as figures in the army and intelligence services. The UN also supported a referral of the case to the International criminal court in the Hague.

In Washington, Obama sharpened his tone after the evacuation of US citizens and said Gaddafi should "leave now". "Gaddafi, his government and close associates have taken extreme measures against the people of Libya, including using weapons of war, mercenaries and wanton violence against unarmed civilians," Obama said.

US pressure will come to bear tomorrow as the secretary of state, Hillary Clinton, flies to Geneva to address the UN human rights council in Geneva.

Labour leader Ed Miliband, writing in today's Observer, said the democracy movements had shown the need for a profound rethink of foreign policy. "The extraordinary events of the past few weeks have served to underline that our alliances should be defined by our values, rather than our values defined by our alliances," he said.